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fix(weakRates): major progress in resolving bugs

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bigs were introduced by the interface change from accepting raw molar abundance vectors to using the composition vector. This commit resolves many of these, including preformant ways to report that a species is not present in the composition and unified index lookups using composition object tooling.

BREAKING CHANGE:
This commit is contained in:
Emily Boudreaux
2025-10-10 09:12:40 -04:00
parent 13e2ea9ffa
commit 2f1077c02d
21 changed files with 17953 additions and 375 deletions
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134
src/lib/engine/engine_graph.cpp
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@@ -79,7 +79,19 @@ namespace gridfire {
// --- The public facing interface can always use the precomputed version since taping is done internally ---
return calculateAllDerivativesUsingPrecomputation(comp, bare_rates, bare_reverse_rates, T9, rho);
} else {
return calculateAllDerivatives<double>(comp.getMolarAbundanceVector(), T9, rho, Ye, mue);
return calculateAllDerivatives<double>(
comp.getMolarAbundanceVector(),
T9,
rho,
Ye,
mue,
[&comp](const fourdst::atomic::Species& species) -> std::optional<size_t> {
if (comp.contains(species)) {
return comp.getSpeciesIndex(species); // Return the index of the species in the composition
}
return std::nullopt; // Species not found in the composition
}
);
}
}
@@ -305,11 +317,18 @@ namespace gridfire {
return 0.0; // If reverse reactions are not used, return 0.0
}
const double temp = T9 * 1e9; // Convert T9 to Kelvin
const double Ye = comp.getElectronAbundance();
// TODO: This is a dummy value for the electron chemical potential. We eventually need to replace this with an EOS call.
const double mue = 5.0e-3 * std::pow(rho * Ye, 1.0 / 3.0) + 0.5 * T9;
// Reverse reactions are only relevant for strong reactions (at least during the vast majority of stellar evolution)
// So here we just let these be dummy values since we know
// 1. The reaction should always be strong
// 2. The strong reaction rate is independent of Ye and mue
//
// In development builds the assert below will confirm this
constexpr double Ye = 0.0;
constexpr double mue = 0.0;
// It is a logic error to call this function on a weak reaction
assert(reaction.type() != gridfire::reaction::ReactionType::WEAK);
// In debug builds we check the units on kB to ensure it is in erg/K. This is removed in release builds to avoid overhead. (Note assert is a no-op in release builds)
assert(Constants::getInstance().get("kB").unit == "erg / K");
@@ -317,7 +336,8 @@ namespace gridfire {
const double kBMeV = m_constants.kB * 624151; // Convert kB to MeV/K NOTE: This relies on the fact that m_constants.kB is in erg/K!
const double expFactor = std::exp(-reaction.qValue() / (kBMeV * temp));
double reverseRate = 0.0;
const double forwardRate = reaction.calculate_rate(T9, rho, Ye, mue, comp.getMolarAbundanceVector(), m_indexToSpeciesMap);
// We also let Y be an empy vector since the strong reaction rate is independent of Y
const double forwardRate = reaction.calculate_rate(T9, rho, Ye, mue, {}, m_indexToSpeciesMap);
if (reaction.reactants().size() == 2 && reaction.products().size() == 2) {
reverseRate = calculateReverseRateTwoBody(reaction, T9, forwardRate, expFactor);
@@ -696,10 +716,20 @@ namespace gridfire {
const double Ye = comp.getElectronAbundance();
// TODO: This is a dummy placeholder which must be replaced with an EOS call
const double mue = 5.0e-3 * std::pow(rho * Ye, 1.0 / 3.0) + 0.5 * T9;
return calculateMolarReactionFlow<double>(reaction, comp.getMolarAbundanceVector(), T9, rho, Ye, mue);
return calculateMolarReactionFlow<double>(
reaction,
comp.getMolarAbundanceVector(),
T9,
rho,
Ye,
0.0,
[&comp](const fourdst::atomic::Species& species) -> std::optional<size_t> {
if (comp.contains(species)) { // Species present in the composition
return comp.getSpeciesIndex(species);
}
return std::nullopt; // Species not present
}
);
}
void GraphEngine::generateJacobianMatrix(
@@ -908,10 +938,20 @@ namespace gridfire {
const double rho
) const {
const double Ye = comp.getElectronAbundance();
// TODO: This is a dummy placeholder which must be replaced with an EOS call
const double mue = 5.0e-3 * std::pow(rho * Ye, 1.0 / 3.0) + 0.5 * T9;
auto [dydt, _] = calculateAllDerivatives<double>(comp.getMolarAbundanceVector(), T9, rho, Ye, mue);
auto [dydt, _] = calculateAllDerivatives<double>(
comp.getMolarAbundanceVector(),
T9,
rho,
Ye,
0.0,
[&comp](const fourdst::atomic::Species& species) -> std::optional<size_t> {
if (comp.contains(species)) { // Species present in the composition
return comp.getSpeciesIndex(species);
}
return std::nullopt; // Species not present
}
);
std::unordered_map<fourdst::atomic::Species, double> speciesTimescales;
speciesTimescales.reserve(m_networkSpecies.size());
for (const auto& species : m_networkSpecies) {
@@ -930,17 +970,39 @@ namespace gridfire {
const double rho
) const {
const double Ye = comp.getElectronAbundance();
// TODO: This is a dummy placeholder which must be replaced with an EOS call
const double mue = 5.0e-3 * std::pow(rho * Ye, 1.0 / 3.0) + 0.5 * T9;
const std::vector<double>& Y = comp.getMolarAbundanceVector();
auto speciesLookup = [&comp](const fourdst::atomic::Species& species) -> std::optional<size_t> {
if (comp.contains(species)) { // Species present in the composition
return comp.getSpeciesIndex(species);
}
return std::nullopt; // Species not present
};
auto [dydt, _] = calculateAllDerivatives<double>(
Y,
T9,
rho,
Ye,
0.0,
speciesLookup
);
auto [dydt, _] = calculateAllDerivatives<double>(comp.getMolarAbundanceVector(), T9, rho, Ye, mue);
std::unordered_map<fourdst::atomic::Species, double> speciesDestructionTimescales;
speciesDestructionTimescales.reserve(m_networkSpecies.size());
for (const auto& species : m_networkSpecies) {
double netDestructionFlow = 0.0;
for (const auto& reaction : m_reactions) {
if (reaction->stoichiometry(species) < 0) {
const auto flow = calculateMolarReactionFlow<double>(*reaction, comp.getMolarAbundanceVector(), T9, rho, Ye, mue);
const auto flow = calculateMolarReactionFlow<double>(
*reaction,
Y,
T9,
rho,
Ye,
0.0,
speciesLookup
);
netDestructionFlow += flow;
}
}
@@ -979,7 +1041,7 @@ namespace gridfire {
m_logger->flush_log();
throw std::runtime_error("Cannot record AD tape: No species in the network.");
}
const size_t numADInputs = numSpecies + 2; // Note here that by not letting T9 and rho be independent variables, we are constraining the network to a constant temperature and density during each evaluation.
const size_t numADInputs = numSpecies + 2; // Y + T9 + rho
// --- CppAD Tape Recording ---
// 1. Declare independent variable (adY)
@@ -1004,13 +1066,22 @@ namespace gridfire {
const CppAD::AD<double> adRho = adInput[numSpecies + 1];
// Dummy values for Ye and mue to let taping happen
const CppAD::AD<double> adYe = 1.0;
const CppAD::AD<double> adMue = 1.0;
const CppAD::AD<double> adYe = 1e6;
const CppAD::AD<double> adMue = 10.0;
// 5. Call the actual templated function
// We let T9 and rho be constant, so we pass them as fixed values.
auto [dydt, nuclearEnergyGenerationRate] = calculateAllDerivatives<CppAD::AD<double>>(adY, adT9, adRho, adYe, adMue);
auto [dydt, nuclearEnergyGenerationRate] = calculateAllDerivatives<CppAD::AD<double>>(
adY,
adT9,
adRho,
adYe,
adMue,
[&](const fourdst::atomic::Species& querySpecies) -> size_t {
return m_speciesToIndexMap.at(querySpecies); // TODO: This is bad, needs to be fixed
}
);
// Extract the raw vector from the associative map
std::vector<CppAD::AD<double>> dydt_vec;
@@ -1049,10 +1120,19 @@ namespace gridfire {
const CppAD::AD<double> adRho = adInput[numSpecies + 1];
// Dummy values for Ye and mue to let taping happen
const CppAD::AD<double> adYe = 1.0;
const CppAD::AD<double> adYe = 1e6;
const CppAD::AD<double> adMue = 1.0;
auto [dydt, nuclearEnergyGenerationRate] = calculateAllDerivatives<CppAD::AD<double>>(adY, adT9, adRho, adYe, adMue);
auto [dydt, nuclearEnergyGenerationRate] = calculateAllDerivatives<CppAD::AD<double>>(
adY,
adT9,
adRho,
adYe,
adMue,
[&](const fourdst::atomic::Species& querySpecies) -> size_t {
return m_speciesToIndexMap.at(querySpecies); // TODO: This is bad, needs to be fixed
}
);
std::vector<CppAD::AD<double>> adOutput(1);
adOutput[0] = nuclearEnergyGenerationRate;
@@ -1157,8 +1237,10 @@ namespace gridfire {
if ( p != 0) { return false; }
const double T9 = tx[0];
// TODO: Handle rho and Y
const double reverseRate = m_engine.calculateReverseRate(m_reaction, T9, 0, {});
// This is an interesting problem because the reverse rate should only ever be computed for strong reactions
// Which do not depend on rho or Y. However, the signature requires them...
// For now, we just pass dummy values for rho and Y
const double reverseRate = m_engine.calculateReverseRate(m_reaction, T9, 0.0, {});
// std::cout << m_reaction.peName() << " reverseRate: " << reverseRate << " at T9: " << T9 << "\n";
ty[0] = reverseRate; // Store the reverse rate in the output vector
@@ -1178,7 +1260,9 @@ namespace gridfire {
const double T9 = tx[0];
const double reverseRate = ty[0];
// TODO: Handle rho and Y
// This is an interesting problem because the reverse rate should only ever be computed for strong reactions
// Which do not depend on rho or Y. However, the signature requires them...
// For now, we just pass dummy values for rho and Y
const double derivative = m_engine.calculateReverseRateTwoBodyDerivative(m_reaction, T9, 0, {}, reverseRate);
px[0] = py[0] * derivative; // Return the derivative of the reverse rate with respect to T9